A locomotive “consist” is a group of two or more locomotives that are mechanically coupled or linked together to travel along a route. Trains may have one or more locomotive consists. Locomotives in a consist include a lead locomotive and one or more trail locomotives. A train will have at least one lead consist, and may also have one or more remote consists positioned further back in the train. More generally, a “vehicle consist” is a group of locomotives or other vehicles that are mechanically coupled or linked together to travel along a route, e.g., the route may be defined by a set of one or more rails, with each vehicle in the consist being adjacent to one or more other vehicles in the consist.
A locomotive will typically include a number of different electro-mechanical and electrical systems. These systems include a plurality of different electronic components, which process or otherwise utilize data/information for locomotive operational purposes. Examples of electronic components in a locomotive include data and voice radios and other communication equipment, positioning equipment (e.g., GPS components), data and video recorders, engine control systems, navigation equipment, and on-board computer and other computer systems.
Certain electrical components may be part of a critical or vital system in a locomotive. In a critical or vital system, one or more functions of the system must be performed with a very low likelihood of failure, and/or with a very long projected mean time between system failures, for safety purposes or otherwise. To achieve this, for those electronic components that carry out a vital function, a locomotive must be outfitted with redundant electronic components. This can greatly increase the costs associated with implementing vital systems in a locomotive. Additionally, even with redundant components in a locomotive, a vital system is still subject to failure if both the primary and redundant components fail.